Simplicity in the mechanical action of a weapon is extremely important, and so it is frequently true that a weapon is considered an advance over previous models because it simplifies the action.
In addition, air guns present some notable advantages over gunpowder weapons, however, air guns also tend to suffer from the problem of overly complex actions. For example, a typical low end lever-action air gun might generate a muzzle velocity of only 275 FPS (85 m/s), and require half a minute to pump up, even though it has numerous moving parts such as a piston, the lever, the lever arm, block, and so on.
Various weapons have used magnetic forces in their actions in various manners. However, these weapons all have more or less traditional actions, which use magnetism merely as an adjunct to some form of mechanical action.
An air gun has been invented, in the parent application to this application, which has as few moving parts as possible in the action, preferably none at all. It has the ability to fire at full automatic, and yet generate, in embodiments, muzzle velocities similar to those of gunpowder weapons.
It is possible to design ammunition specifically tailored to this unique new type of weapon.
Such ammunition would not be similar to that for a rail gun (a gun using magnetic forces to accelerate the rounds). Such weapons are enormous, heavy, expensive, and in fact not yet working in any practical manner outside of the laboratory. The enormous muzzle velocities generated by rail guns render the ammunition they use automatically fatal, the enormous recuperation energy required between shots renders them extremely slow to fire.
The air gun of the parent application on the other hand develops more or less normal muzzle velocities comparable to a low-power gunpowder weapon and fires more rounds per minute than any known air gun. The motive force is provided by a large reservoir of compressed air, not magnetism. Magnetic forces are used in place of a breech block.
Thus appropriate ammunition for the weapon will be small, light, inexpensive, ferrous (meaning magnetically responsive, not necessarily iron based), and since the magnetically chambered action of the air gun does not handle rounds individually, it will also be spherical.
Cost of ammunition is a growing issue and for a gun, such as that gun of the parent application (whose full disclosure is incorporated herein by reference) which fires a simply enormous amount of ammunition, ammunition cost is an extremely significant expense. While the material for a single round of ammunition may be bought at pennies in bulk, a gun which fires (as taught by the parent application) at a cyclic rate of 10,000 RPM or higher will rapidly run up the cost of even inexpensive ammunition due to sheer quantity. Thus it would be preferable to provide an inexpensive material for ammunition for air guns, especially for magnetically chambered airguns.
Spent ammunition is further becoming an issue. For example, depleted uranium core ammunition (prized for armor piercing rounds due the very high density of uranium) is only mostly depleted: the uranium remains slightly radioactive. Worse, uranium is itself a poison in the non-radiation sense. When such rounds are fired, an environmental issue can be created. Similar issues apply to other types of ammunition, even lead in old style small arms ammunition, which is a well-known environmental contaminant and so on and so forth. It would be preferable to provide materials for ammunition which are less prone to contaminating the environment.
It would further be preferable if the ammunition provided a ready means for customization close to the end user.